Anybody know how i can clean these smudges off my F900 Sensor myself?

[Mike Krumlauf]

The local repair guy is asking $490 to clean this (BS)... i have to believe there is a way i can carefully do this myself. They are on the inside part of the last piece of glass before the CCD Sensor, they are NOT on the glass attached to the color or ND filter wheel.

 

[cyvideo]

Hmm! If as you are saying that you think that these smudges are on the backside of the LPF then it is quite easily cleanable. That section of glass you show is a Low Pass Filter. I suspect though that what you are looking at are not smudges on the back of the LPF. More on this later. If they are indeed smudges such as finger print grease the LPF can be removed by undoing the surrounding screws that hold the LPF in place and gently withdrawing it from is resting position. From your local optometrist get hold of a good quality lens cleaning solution suitable for coated glass spectacles. Also grab one of their best glass cleaning cloths. I always used to use a fine real leather chamois for this type of cleaning operation. Go ahead slowly and carefully and remove the LPF. When cleaning these LPFs front side or backside use a 90 degree up-down and 90 degree left-right cleaning motion. NOT around and around.

Now my concern. If these are not smudges on the backside of the LPF they could indeed be the first signs of separation. Most of these LPFs are made from a series of laminations of 2/3 or 4 slices of treated optical glass elements bonded together. What can and does happen over time is that the bonding agent that 'glues' these elements together starts to deteriorate and starts to go opaque. If this is what is happening this is terminal. In which case the only solution is to replace the LPF. I've done this on numerous 2/3" cameras over the years. All various Sony models up to and including the PDW-800 series XDCams. Here in Aussie the LPFs are about AU$500.00. Once replaced the camera is a good as new and ready to roll. If it's a Sony camera and you have a service manual you will find a reference to the LPF similar to this example:

"Filter unit, optical 1-479-899-11 (<this will be a part number)

It can become nebulous (intransparent and whitened) with elapse of time. Then it will not meet the required characteristics. Replace it as needed."

Hope it is just finger smudges. If they are it would indicate some ham fisted person has handled the LPF without good care and attention.

Good luck!

Chris Young.

 

[Mike Krumlauf]

Thanks for the detailed response Chris.. Per your idea, When i had the camera at work (i work at VER), the camera tech saw the smudge and began to take the low pass off (thats the first piece of glass connected by the three screws and is teal blue in color right?) He then took a color filter out and an ND filter out and thats how we realized its on the very last piece of glass before you reach the CCD itself. My thoughts is its a drop of electro cleaner that dripped off one of the boards when it was being cleaned. I tried opening up the CCD block and almost bricked the camera so im taking that as a sign to not mess with it anymore. The spot is only seen on my lens' lowest T-stop which is 22. if i shoot wide open or even mid range with ND its not noticeable at all. If i had a very skinny and small cleaning stick i could put in the rivit between the CCD and this glass that would be awesome, but, i dont think they make sensor wipe brushes that small